Science Says: Better to Be A Boy Than A Girl

Jamie Reidy summarizes a wonky scientific study.


As Nancy Shute explains in her article for, scientists may now understand why a little dirt early in life is a good thing.

Researchers at Brigham and Woman’s Hospital in Boston published their results in

They found that microbes in the gut keep a rare part of the immune system reined in. No microbes, and the immune cells go crazy in the lungs and intestines, increasing the risk of asthma and colitis. Add in the microbes, and cells in question, invariant natural killer T cells, retreat.

So, Helicopter Parents, step awaaaaaay from the Purell.

But the most exciting revelation from the study – perhaps due to the journalist’s gender bias??? – appears buried at the end of Ms. Shute’s article:

There’s even some evidence that women might have more autoimmune diseases than men because they’re kept cleaner than boys as children.

Can I get a Yea-men on that?

So, all kidding aside, parents, will you let your toddlers get dirtier?

Photo by: stevendepolo


About Jamie Reidy

Jamie Reidy is a former U.S. Army officer turned little blue pill pusher turned author. His first book "Hard Sell: The Evolution of A Viagra Salesman"
served as the basis for the movie "Love and Other Drugs" starring Jake Gyllenhaal. Jamie is currently writing his new book, "Game On: One Fanatic's Fantastic, Foolish and Futile Attempt to Attend 365 Sporting Events in 365 Days." He discovered his latest story featured on Good Men Project - "Hope Shoots and Scores" - on Day 39 of his crazy journey.


  1. Anthony Zarat says:

    Hygine theory is gaining increasing acceptance:

    * Children born in farms have virtually zero allergy and asthma — and much lower incidence of auto-immune diseases.

    * Children raised in very clearn and/or steril environments have the opposite outcomes (increased allergy, asthma, and auto-immune diseases).

    Keep in mind that auto-immune damage plays a role in heart disease and some cancers. This is important stuff. Dirt and non-pathogenic bacteria (the kind that exists all around us in a normal, non-sterile environment) is an essencial part of the development of the immune system.

    However, the picture that accompanies this article is very deceptive. These changes all occur in the first two years of life. The boy pictured above is out of the sensitivity window, as it is currently understood in hygine theory.

    If you are thining to yourself “why don’t I know this”, my answer is, the home-hygine product industry speaks louder than scientists and health care experts. They want to sell you home-sterilization as a “good parnet” duty, and people are buying the BS, and hurting their children.

    Just let toddlers run around in a grassy area (park/backyard). Your children will know what to do. Avoid for big-seed trees like Hickory (pig-nuts can be choking hazards). Other than that, let the kids stick whatever they want into their mouths.

    • Anthony Zarat says:

      By the way, one reason hygiene theory was slow to gain acceptance is that, early on, it was known by a confusing collection of different names. This has changed. If you google “hygiene theory” or “hygiene hypothesis” you will find numerous modern studies (and a wiki article). This is significantly past the “proposed” point. It is broadly accepted. As a parent, I have no doubts. My sons were both grass eaters as toddlers (even though I have a giant pig-nut Hickory tree in my backyard, curse my luck!)

  2. Tom Brechlin says:

    I’ve been saying for years that I feel this germ phobic attitude is not good for kids. Being exposed to germs allows your body to develop antibodies to fight off infections. The body is amazing and it works to survive.

    Boys are simply more apt to play in dirt. While Annie is playing tea time with her dolls on the patio, Jimmy is throwing mud at her. When I see people incessantly wiping a kids face, I wonfer if the kid is ever exposed to anything.

  3. no gender bias… the study seems legit though. Let the kids play, and build up a strong, battle-tested immune system…

  4. Jamie Reidy says:

    Hey, Jeff! Thanks for reading, and even more sO for taking the time to comment.

    I was actually just being a wiseass about “gender bias.”

    • Anthony Zarat says:

      I doubt there is a gender side to this. These immune changes are concluded LONG before sex hormones show up. I know it is tempting to go there, but the science does not back it up. Let boys be boys, let girls be girls. By the time children are old enough for socialization, expectations, and so forth, their immune system is mature.

      I love dirty boys who are dirty, and I love girls who are dirty, and I love boys who are clean, and I love gilrs who are clean, and I love that hygiene theroy has nothing to say about any of it!

  5. I generally hold the policy of ignoring science journalism and looking up the actual studies cited, because generally things get misread or extrapolated too far.
    This example from NPR is one of the less sloppy examples of science journalism. It didn’t diverge too far from the journal article it cited (titled “Microbial Exposure During Early Life Has Persistent Effects on Natural Killer T Cell Function”) in describing the article.
    I’m having a hard time trying to decide if Mr. Reidy is criticizing Ms. Shute for including the concluding extension citing a different NPR interview about a different study instead of staying focused on the “Microbial Exposure…” article, or if he sincerely believes that Ms. Shute cited the “Microbial Exposure…” article in discussing gender differences in autoimmune diseases (Ms. Shute did not, in fact, cite the “Microbial Exposure…” article).
    If his intention was the latter, maybe he’d like to comment on the NPR interview Ms. Shute cited instead of jumping to the conclusion of journalistic bias???

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